Hope it can be solved. There is a graph below P is any point in the square ABCD, and the area of triangle AOD is m and the area of triangle DPC is n, then what is the area of square ABCD? square: A·→ →→→→·D ↑ ·P ↓ ↑ ↓ ↑ ↓ ↑ ↓ Please note that I didn't draw the line of the triangle. The point behind a is aligned with the point in front of P. I haven't done it well, so I have to draw it in my own house to solve the problem.

P is any point in the square ABCD, and the area of triangle AOD is m, (here should be triangle APD) the area of triangle DPC is n, then what is the area of square ABCD?
The area of square ABCD is 2 (M + n)
Because the area of △ APD + △ DPC = m + n is half of the square
So the area of the square ABCD is 2 (M + n)

The complex z = (1-I) 2 / 2I. Try to change Z into a + bi form

Z=(1-i)²/2i
＝（－1+1－2i）/2i
=-1+0i

Hope it can be solved as soon as possible! With a wooden stick, draw 10 paragraphs in red, 12 in blue and 15 in yellow. How many paragraphs have been divided by three pens Tip: there are places to repeat (use the least common multiple)

Calculate the number of coincidence
It is divided into 10 sections, 1 / 5, 1 / 2, 4 / 5
It is divided into 12 sections, 1 / 3, 1 / 2 and 2 / 3
It is divided into 15 segments, 1 / 5, 1 / 3, 2 / 3, 4 / 5
There are 9 + 11 + 14 points divided into several sections. Subtracting 5 overlapping points, 29 points are obtained and 30 segments are obtained

Fold a piece of rectangular paper and cut out an isosceles triangle. Cut the isosceles triangle into two right triangles of the same size. Then cut the two right triangles into convex quadrilateral. You can make them______ Different kinds of quadrilateral

As shown in the figure, when the hypotenuse of two triangles coincides with each other, a rectangle and Zheng shape can be made,
Two parallelograms can be made when equal right angles coincide with each other,
Four kinds of quadrilateral can be made
So the answer is: 4

There are 22 students participating in mathematics extracurricular activity group, 18 students participating in physics extracurricular activity group, 16 students participating in chemistry extracurricular activity group, and 36 students participating in at least one subject extracurricular activity group?

According to the title, 36 = 22 + 18 + 16 card (a ∩ b) - Card (a ∩ C) - Card (B ∩ C) + card (a ∩ B ∩ C),
So card (a ∩ B ∩ C) = card (a ∩ b) + card (a ∩ C) + card (B ∩ C) - 20 ≥ card (a ∩ B ∩ C) + card (a ∩ B ∩ C) + card (a ∩ B ∩ C) - 20
The solution of card (a ∩ B ∩ C ≤ 10,
Therefore, there are at most 10 students who participate in the three subjects extracurricular activities group

1. The students from the biology group of Xingxing primary school collected specimens. The butterflies collected were two-thirds of dragonflies and one fourth of beetles. There were 12 butterflies and how many beetles?

Butterflies are two thirds of dragonflies, and there are 12 butterflies,
The number of dragonflies was 12 × (2 / 3) = 18;
Dragonflies are a quarter of the beetles,
The number of beetles is 18 × (1 / 4) = 72

If M

Original formula = 2m + (- M) + (- M) + M
=2m-m-m+m
=m

There is a pile of stones. If 9 tons of trucks are used to load the stones, 7 tons are left; if 12 tons of trucks are used to load, 10 tons are left; if 15 tons of trucks are used to load, there are still 13 tons left, how many tons of stones are left?

If this pile of stones is two tons more
All three kinds of trucks can be used to load them
The least common multiple of 9, 12, 15 is 180
So this pile of stones is at least 178 tons

A prime number is a two digit number. If you exchange one digit with ten digit number, the two digit number will still be prime number. Can you write such a prime number?

11,13,31,17,71,79,97,

When Xiaoqiang and Xiaoli go shopping in the supermarket, Xiaoqiang uses up seven eighths of the money she brings, and four fifths of the money she takes with her. They have the same amount of money left. The ratio of their original money is () How is it calculated My classmate said it was 32:35

1-7/8=1/8
1-4/5=1/5
Therefore, 1 / 8 of Xiaoqiang's money is the same as that of Xiaoli
So, the original money ratio was 8:5